Alfred koehn



(N0 Model.)

A. KOEHN.

ADJUSTABLE STANDARD FOR MUSIG'RAGKS. No. 398,408.

flirllrlrlllflllllllll N PETERS, Plmm-Lnhn m her. Washmgmn, D C.

UNITED STATES PATENT Fries.

ALFRED KOEHN, OF NE\Y YORK, N.

ADJUSTABLE STANDARD FOR MUSlC=-RACKS.

SPECIFICATION forming part of Letters Patent No. 398,408, dated. February 26, 1889.

Application filed Feptem'ber 21, 1888. Serial No. 286,003. (No model.)

To all whom, it may concern.-

Be it known that I, ALFRED KOEHN, of the city, county, and State of New York, have invent-ed certain new and useful Improvements in the Construction of Adjustable Standards; and I do hereby declare that the following is a full and exact description thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon, making a part of this specification, in which- Figure 1 is a central vertical section of my improved extension-standard for music-racks, lamp-stands, and other purposes. Fig. 2 is a detail view, in like section, illustrating the holding-catches when released; and Fig. 3 is a detail, partly in section, of the upper end of the standard, showing a modification thereof.

The object of my inventionis to provide an adjustable extensible standard which shall be simple .in construction and permit of ready adjustment to different heights.

It consists in the combination, with an adjustable tube telescoping within a fixed upright tube secured to a suitable base, and with a rod playing longitudinally within the adjustable tube and fitted with a spring to up hold it, of a pair of swinging catches, each pivoted at one end to the lower end of the adjustable tube and at the other to a link, itself pivoted to the lower end of the rod. The catches thus form a double toggle-joint, which operates under the stress of the spring to cause the outer ends of the catches to engage automatically the inner surface of the lower fixed tube, and thereby prevent the descent of the adjustable tube without interfering with its cent. The catches are released by a depression of the rod within the tube eifected by suitable pressure upon the upper end of the rod.

In the accompanying drawings, A represents a tubular upright standard firmly fixed in a suitable base, B, and closed at its upper end by a cap, C.

D is an extension-tube passing centrally through. said cap 0 and secured at its lower end to a plunger, \Y, fitted to play freely within the standard.

E is a central rod extending longitudinally within the .extensioutube D, to project and play through the plunger lV at its lower end per end of the tube D. A spiral spring, G, fitted within the tube D, engages the rod E and operates automatically to lift it upward.

Gatcl1-bars H H are pivoted at their inner ends to the lower face of the plunger lV at diametrically-opposite points, one on each side of the projecting end of the rod E, and these catch-bars are severally coupled to the end of the red by means of pivoted links K if, so that the upward tension of the spring G upon the rod will operate to force the ends of the catch-bars outwardly against the inside face of the tubular standard A. The ends of the catches thus brought into frictional contact with the, standard are beveled to present a sharp angle for contact, so that the stress of the spring G will suffice to give them such a hold against the face of the standard as will positively prevent the cxtension-tul'ie from dropping therein, the hold of the catches be coming, by reason of their angle of inclination, more firm and sure in proportion as the weight upon the extensioirtube is increased. These catches H H are readily released from the standard A by pushing the rod D downward against the stress of its spring, as shown in Fig. 2.

The head F upon the upper end of the extension tube D is transversely slotted at L, and the upper end of the catch-rod E terminates within said slot. The depression of the catch-rodto release the catches may be effected by simply pressing upon its upper end with a finger inserted for the purpose in the transverse slot or opening L in the head, the end of the rod being fitted with a knob or button M, as shown in Fig. 3. Preferably, however, a lever, N, is pivoted at one end within the slot L, as shown in Fig. 1, toeX- tend transversely over the end of the catchrod E and rest thereon, its outer free end being bent downward, as shown at P in Fig. 1. By pressing this bent end P inward with a grasp of the hand the rod E will be forced downward and the catches H H released to permit the tube D to drop, and its downward movement will be automatically arrested so soon as the lever is relieved from pressure at any point by the tension of the spring G operating, in the manner described, to throw out the catches.

and through a head, F, secured upon the up- The extension-tube D is free to be raised at mines the force of said engagement, have heretofore been combined with a sliding rod y forked at its lower end to bear directly upon said grippin jaws to release them; but my invention d1 fers therefrom in that I couple the lower end of the rod by means of links to the two jaws, and form thereby a toggle-joint by means whereof the engagement of the jaws is readily enforced by an upward movement 3 of the rod produced automatically by means of an encircling spring, or in other suitable manner. I thus producea more efficient and compact device at less cost, and which is not wholly dependent upon springs for its action.

I claim as my invention- The combination, in an adjustable standard, as described, with a tubular upright secured to a supporting-base, an adjustable tube moving longitudinally within said standard, and a movable catch -rod extending through said tube of the two catch-bars hinged to the lower end of the adjustable tube to swing outwardly into contact with the inner side of the inclosing-standard, and the links coupling the free end of each catch-bar with the lower end of the rod, substantially in the manner and for the purpose herein set forth.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

ALFRED KOEHN. \Vitnesses:

A. N. J ESBERA, E. M. WArsoN. 

